On September 10, 1814, John Quincy Adams, son of the second president of the United States and destined to become its fifth, the most accomplished American diplomat of his generation (and perhaps the most able in American history), conversant in half a dozen languages, was, as usual, dissatisfied with his colleagues, his compatriots, his predicaments, and most of all, himself. He had just turned forty-seven, noting in his diary that "two-thirds of the period allotted to the life of man are gone by for me." As he contemplated the days of his life, his remorseless New England conscience informed him, "I have not improved them as I ought to have done." Nonetheless, on this autumn day he continued conscientiously to discharge one of the many duties that gave structure and meaning to his life. It was a duty that he performed after rising—as he usually did—between five and six in the morning, lighting a candle and kindling a fire, reading in the Bible (with commentaries) for an hour, followed by an austere breakfast consumed alone.

He was writing a long, gloomy letter to his mother, Abigail Adams.

Adams wrote from Ghent, in what is now Belgium, where he led (after a fashion) a delegation of five peace commissioners negotiating with their British counterparts for an end to the War of 1812. He had told Abigail at the outset, in January of that year, that he thought war a bad idea. Writing from St. Petersburg, where he then served as minister representing the United States to Russia, he had said, "We could gain nothing and could not fail to lose something of what is worth more than all other possessions to a nation, our independence" from such a war. He had no doubt about the justice of America’s stand, of course. Both Britain and France had treated the United States badly, in his view, the former attempting to reap commercial advantage from her naval dominance of the globe, in the process abusing American rights by impressing her seamen and blocking her trade. Napoleon’s France, as he knew from close observation in Europe, had embarked on a course of limitless expansion.

Adams considered these injustices and their remedies with characteristically cold clarity. He thought both England and France were doomed to fail in their overreaching ambitions, their insane "spirit of ambition, glory, and conquest." At some point, he acknowledged, the United States might have to defend itself—"to forego the right of navigating the ocean would be a pusillanimity which of itself would degrade us from the rank and rights of an independent nation," he wrote Abigail in May, as his views hardened. But though he favored military and naval preparedness, he understood the odds. Even if the United States Navy were four or five times its current size, a fleet of thirty frigates (rather than the actual seven), and a squadron of ships of the line (rather than none) it could only irritate the mighty Royal Navy with its 180 frigates and 150 ships of the line. An army of five or six thousand, backed by an undisciplined and ill-trained, if numerous militia, could barely hope to defend American ports.

England "has vulnerable parts," he thought, and the United States might strike at them. But he expected little in the way of sustainable military success, and events proved him correct...